[PATCH] D30751: [MachineCopyPropagation] Extend pass to do COPY source forwarding

Geoff Berry via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Apr 28 08:22:57 PDT 2017


gberry added a comment.

In https://reviews.llvm.org/D30751#740258, @MatzeB wrote:

> For the record: This looks very similar to https://reviews.llvm.org/D20531 and https://reviews.llvm.org/D21455. Though the earlier two attempts were somewhat sketchy in terms of correctness as they were renaming physregs and we have no good way in LLVM to detect which ones are legal to rename.


Yep, that's why I added you and @jonpa as reviewers and mentioned the previous changes it in my comment on 3/14 :)
I think this version avoids the issues of the previous two attempts by running when we still have virtual reg information.


https://reviews.llvm.org/D30751





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